The four projects are the American Law Institute's Model Penal Code, the proposed Federal Criminal Code recommended by the National Commission on Reform of the Federal Criminal Laws, and the criminal code revision bills sponsored by Senator Kennedy and by Congressman Drinan. The major innovation in recent reform proposals is reduction of sentence disparities through establishing sentencing guidelines. In principle, guidelines involve formulas reflecting the seriousness of the offense and various characteristics of the offender, such as age, mental condition, and dependents. For each combination of offense and offender scores, a presumptive sentence or permissible range of sentences is designated. Generally, grading should reflect the dominant and feasible purposes of short, medium, and long sentences. For example, very long sentences, which can be justified only as an incapacitation of dangerous personalities, should be available only where relevant findings are made. Medium term imprisonment must rest on a plan to rehabilitate. Regulation of sentencing by guidelines can be accomplished under strong legislative directions and by appellate judicial review of the application of such guidelines. Judicial review, available to the prosecution as well as the defendant, will go far towards eliminating disparities and introducing rationality in sentencing. Pennsylvania sentencing guidelines and 178 footnotes are appended.